Air conditioning apparatus for enclosures of aircraft



Dec. 28, 1954 w. F. MAYER 2,597,917

AIR CONDITIONING APPARATUS FoR ENoLosUREs oF AIRCRAFT Filed sept. 15,1951 Constant Efficiency 2q,

LnesA-j E u, l/ zsooRPM '53g l/ /I (Tokeoff) 24ooRPM En /l LyJ/wmbf z; E1 l c zooo RPM E; \/(Cruse) 1f e. wmf/wefmf/5e, $2 3 INVENToR. E 1 N200RPM (Ground) BY 7 o INTAKE voLuMe FLow RATE AT ANY ALTITUDE rroef/E/United States Patente. O

f @697,917 umgcosmnosnsc ArrAnarUs non ENcLosUREs-on AIRCRAFT WaldemarF. Mayer, Las Angeles, calin, sjs ig"m i r" t vThe GrrettCorpra'tio,Los'ng'les, Calif., acrporation of california Applikation-'september'15,"19s1', serirNmMesss reclaim. (cinzia-'46) l. .Tim Present ,iavn'tiorelates generally to. .air .condiacnma andas la Particularly governed.with novel apparatusforfthe r conditioningfand yentilation ofenolosuresfgenerally', and is specially adapted for enclosures such' asthe compartments and'cabin 'spaces of aircraft.

Hetofore in`lngine`"`dr`ive aircraft, ithas been the practice inconventional air "conditioning systems to sup-` ply a constantweight'airdlovv to .t`he`aircraft cabin. .Sucharrangements"'necessitated vthe 'tilizatfi'on'of 'a variabl`e ratiotransmissi" in 'orderto comply 'with ythe' varia- Vtlons inengine"speedandfor in density of the'am-bient air.

` The 'apparatus ofthe present` invention differs from` the Yaircraft":fabing `yielding a'fmorefuniforrn Ventilating ow thtough"fthe ica'bi'n"at different "cabin pressures. Novelcontrolisprovided for modulatingVthe'air cooling Ainj response to s peed':` changes and"va`riation`in'the lintake kflowfrate'of the' compressor.

'For ventilating"the-enclosure; when Athefaircr'aft is on the ground, uniq`u'e valving is providedsothat the intake of the compressor'rnaybejco'nnected to vthe enclosure, fwhereuponfambientai is drawn intotheenclosure'for Ventilating purposes.

According to th'ej' generalxpncept of' the present invention, it is oneobject toprovide. air conditioning 'apparatus for supplyingconditioned'air to an enclosure, wherein air pumping means may bedrivenby a" power ldevice'which may be operated at dierent speeds underpredetermined Aconditions -ofl operation, fno'vel means' being arrangedto modulate-the air f rornthe pumping meanssoas to maintain required*pressure and temperature valves in the enclosure.

` Suchfapparatus isparticula'rly useful inaircraft as it permits drivingof `air""purn'p ing devices from a main engine; thus eliminating thenecessity V'for vari'able' ratio transmission by which the air' pumpmight`V supply a substantially constant'qweightairow to vthe enclosure.

vA further object offthe inventionis to provide in air c'onc'lition'ngapparatus`,' improved control means for con- *trolling pressureanditemperature of fluid for conditioning an enclosurein responsetovariations in driving speed of the pumping means-for supplyingsaidjliuid, vand variations in the Velocity offiluid'intake to the airpumping vrrneans, or variation' inr'tempera'ture risek across the air'pmpinanieans- Afu'rfther object of the` vention is to` increasethe arrflow jr'atesand coolngjcap ty of a. compressor for a^svelprnssiblepagina torque; bytecding. back .energy fr ecovered fromcompressed air dellvered byv thecompressor. `Astill furtherobject "jis'to provide -air conditiomng 'apparatus of'thelcharacteridescribed, whichis operable, foreiiar'nple, in the*`cz 1 s e`r ofaircraft for coolinganen- `closureduringightor whenonthe ground, but which E'mayreadilybemodifiecl as to its operation onthe ground v,so asjto merelyfl rculat eambienti air" through the en- 2closurefor 'ventil'ating pu oses Furtherobjects of tl1e"'invention` will be brought out in the following part ofthe specification, whereinldet'arled 2,697,917 Patented Dec. 28, 1954ICC 'de sfcfription isfforthe purpose of fully disclosing the inventionWithout I'Jlacing` limitations thereon.

Referringto 'the 'acicompanyingdawinga which are forillustrativepurp`oses 'only:

" Fig 1 is 'aVievv` diagrammaticallyillustrating 'air conditioningapparatus embodying the features of the present invention: and Fig'. 2isa typlcalcurve for an airconditioning system embodying the presentinvention, 'and showing the' points of control forfour basic'operational requirements of'an aircraft. Referring "now generally1to'thedrawings, for illustrative purposeafthe air conditioningapparatus ofithepresent "invention is'shown' 1n'F1g. 'l as 'comprising a'centrifugaltype 'air' compressor A10 whichV has its impeller v11 opera- 'tively'.connected 'through speed -'changer 12 tov the drive "shaft 13' of an'aircrafr'main engine 14.

[The compressor" 10"ha's aninlet connectionlScon- `nectedthrough asupply'duct `-16 having 'an vintake end opening 17 in communication witha supply source-of "cabin `air, in this i instance ambient tair.

The compressor 10 'jha s` an'outlet'connection 18 with a heat exchanger19 through 4which'compressed"air from "the compressor 10 is conducted inheat exchange relation connects at itsoutlet`23 with a duct 24 by whichIthe conditioned air is conducted to an enclosure 25,; such as a`compartment or' cabin of 'any aircraft.

The component yparts ofthe air conditioning apparatus as thus fardescribed-,areeintheir broad aspect the same as incorporated in aconventional Vair conditioning system wherein it is the practice tosupply a constantweight airrow to the`4 enclosure. However, insteadv ofutilizing ya'yariable ratio transmission so as to maintain a practicallyconstant* air Weight ow 'rate it is proposed to .operate the compressorof the present invention'at speeds which correspond'with theoperationalspeed requirements of v thev main' aircrafty engine.

vrIn this respect, there' are four basic operational requirements,namely:

l'. Ground coolingwhenengineruns at 1200 R. P. M.

2."Take off` at lowaltitudes at 2800 R. P. M.

3. Climb toaltitu'de at' 2400 R'. P; M.

4. Cruise athigh altitudes at 2000 RL P. M.

While ambient air' pressure 'and temperature variesvery greatly,thecabin air has to be'` conditioned to comfortablevalues. As shown inthe curve in Fig. 2, utilization of a centrifugal type compressor Vgivespressure and temperature rises which increases rapidly with enginespeed,

'whileV the volume ow rate does not vary' so rapidly.

It therefore is evident-that' inA order to prevent any surging o f thecompressor and to obtain etlicient operation, it is necessaryfto controlthefunction of the apparatus.

The selected control line26 produces a satisfactory "averageloperation,and by regulating the apparatus in a manner to'hereinafter be explainedto give operating points at the"intersecti`ons of the control line andthe respective speed lines, for example,point C for 2000 R. PJM.,compressor'speeds directly following the main "engine y'speed maybejutilized.

ldamage to these devices.

The speed changer 12 incorporates an auxiliary plane- "tary` changegearsectionZS` which may be actuated by means of a'control lever'29 fromaneutral disconnected position N to selective positions H or D In theformer position," 'the compressor is connected forfhigh speed'operation`,lf or'enarnpljin the ratio of 233:1, while 1inthe latter;position the compressor is connected for 3 direct operation, forexample, 1:1 ratio. Another section 36 or the speed changer incorporatesspeed increasing gearing in the ratio or', roi example, 10.311 so as toincrease the impeller speed ot' the compressor to as much as 46550() r.M. at 2800 R. P. M. engine speed.

The inlet side ot' the air turbine 2li is connected through a portopening 33t and ow passage 32 to provide a bypass connection between theinlet side of the turbine and its outlet 23 under control of a valve 33which is arranged to adjustably seat in the port opening 31. This valveis controlled in its position coactively in response to speed changesand variations in ow-rate or intake volume of air to the compressor aswill now be explained.

'i he valve 33 is normally biased toward closed position by a spring 34,while the valve opening position is adjusted and varied by means of aservo-motor 35 or other suitable control means. As shown, theservo-motor contains a piston 36 which is operatively connected with thevalve 33. The movement of the piston is controlled by a pilot valve 37having an actuating stem 38 which connects to an intermediate point 39of a floating lever arm 4b.

Speed changes are carried to one end of the lever arm trom a centrifugalregulator 41.

The intake volume of air being supplied to the compressor lb is measuredby speed of a ow-rate meter fan 42 which is positioned in the duct ll6in the path of air ow therein. This fan is connected with a generatorand amplier 43 which is electrically connected to energize a solenoidcoil 44 of solenoid 45, this solenoid being spring loaded by spring 46.The solenoid is connected to the opposite end of the floating lever arm40 to that at which the centrifugal regulator is connected.

Movements ot the floating lever arm are carried to the pilot valve 37',the operation of which controls the application of fluid pressure, whichmay be from an oil pump, as shown at 47, having a supply connection withthe pilot valve through a conduit 43. The pilot valve acts toselectively place oil pressure above or below the piston 36 throughconnections 49 or 50, respectively, or shut ott these connections tolock the piston 36 in a position of its adjusted movement.

Cabin temperature control is regulated by providing a bypass connection5l between the outlet connection i8 of the compressor and the outlet 23of the air turbine 2l to which the flow is conducted through a portopening 52 which is controlled by means of an associated valve 53. Thisvalve is electrically controlled, in this instance by a solenoid havingan actuating coil 54 which is energized to open under control of a cabinthermostat 55.

Conventional pressure regulating valves are indicated, for example, asuitable valve 56 regulates the cabin air pressure, a pressure reliefvalve 57 being provided to open upon maximum predetermined amount ofcabin pressure, and vacuum relief valve 58 being provided to open uponthe occurrence of a minimum predetermined value of cabin pressure. Thesevalves operate in a manner well understood in the art, and furtherdescription is thought unnecessary.

During flight operations of the aircraft, coolant air is supplied to theheat exchanger 19 by ram air flow through the duct passage 20. However,on the ground, during no ilight condition, other means must be providedfor circulating coolant through the heat exchanger. This is accomplishedby providing an air moving device in the duct 2t). This device is shownin the present instance as comprising a fan 59 having a drivingconnection through a speed increaser 60 with a driving air turbine 61.The component parts of this unit are streamlined and mounted in anacelle housing 62 positioned on the discharge side 'of the heatexchanger 19 so as to provide suction i'low of coolant air therethroughduring operation. The air turbine is supplied with operating air fromoutlet connection 18 through a bleed connection 63, a control valve 64being interposed in the bleed connection for manually controlling theoperation of the air turbine.

The apparatus of the present invention is further arranged to act merelyas Ventilating apparatus by means of which ambient air may be circulatedor drawn into the cabin by actuation of the compressor 10.

For this purpose, a flow duct 65 interconnects the duct 24 with thecompressor inlet duct 16. The ends of the duct 65 are normally closed bybuttertly valves 66 and 67, the latter valve also being arranged innormal position to close an overboard discharge port opening 63. Thesevalves are interconnected for concerted operation, and when actuated totheir dotted line positions, air may be drawn from the cabin 25 throughthe duct 65 by the action of the compressor l0, and discharged overboardthrough the opening 68. In this position of the valves, inlet tlow tothe compressor through opening 17 is cut off, and also ow from outlet 23directly into duct 24 is cut o.

Operation of the air conditioning apparatus of the present inventionwill now be further considered. During flight, the lever 29 of theplanetary change gear section o the speed changer is set for directdrive at position "D, and the valve 64 is closed since ram coolant airwill be supplied to the heat exchanger 19.

Let it now be assumed for purposes of discussion that the engine 14 isoperating at a given constant speed, for example, 2000 R. P. M. The airintake volume and temperature rise under such conditions will beapproximately as indicated by point C on the speed curve for 2000 R. P.M. as shown in Fig. 2. The intake volume of the compressor lil ismeasured by the meter fan 42 which will energize the solenoid coil 44,each flow-rate determining a certain solenoid position. Engine speed isregistered by the centrifugal regulator 41. The operating elect of thecentrifugal regulator and the solenoid 45, when operating on the controlline 26, as shown in Fig. 2, is laid out so that the pilot valve 37 isin neutral position locking the valve 33 in its proper position for theassumed condition of operation.

Change in engine speed will act through the centrifugal regulator toactuate the pilot valve to set the valve 33 into the required newposition, and the change in the intake volume ilow to the compressoracts to restore the pilot valve to its neutral position shutting oitconnections 49 and 50 so as to lock the servo-motor at the new positionot the valve 33. For example, assuming that the speed is increased, thecentrifugal regulator 41 will swing the connected end of floating leverarm 4d in a counterclockwise direction so as to move the pilot valvetoward the left, whereupon oil pressure is supplied through connect1on49 to the top side of piston 36, with the result that the valve 33 movesdownward to a further opened position so as to bypass a greater amountof air around the air turbine 2l. Increased volume of intake air to thecompressor it@ will more strongly energize the solenoid coil 44 whichwill now act to move the lower end of the Floating lever arm 40 in acounterclockwise direction thus restoring the pilot valve 37 to itsneutral position locking the piston 36 in a new operating position ofvalve 33.

For ground cooling, the lever 29 is moved to H position which will lockthe ring gear of the planetary gearing to the frame so as to actuate thecompressor at high speed. Under such conditions, the compressor willdeliver h igh temperature, high pressure air. A portion of this air isbled off throughv connection 63 by opening the valve 64 to permitdelivery of actuating air to the turbine 6l. The fari 59 being thusmotivated causes ow of coolant air through the duct passage 20 of theheat exchanger 19. Air from the compressor 10 is thus lrst cooled in theheat exchanger 19 and from there is further cooled and reduced inpressure by passage through the air turbine 21. Temperature control ofthe cabin is accomplished as previously described by controlling flowthrough the bypass connection 51 by means of valve 53 in response tocabin thermostat changes.

Under certain conditions, it may be desirable to merely ventilate thecabin or enclosure rather than to provide cooling as justdescribedabove. Since this operation does not utilize the heat exchanger 19 thevalve 64 may be closed and the circulation of coolant to the heatexchanger discontinued. For Ventilating the cabin, the valves 66 and 67are actuated to dotted line positions as shown in Fig. l. This connectsthe duct 65 between duct 24 and duct 16 so that the operation of thecompressor 10 will now draw intake air from the cabin, the air Elowthrough duct 24 being in reverse direction to its direction of fiow whencooling the cabin. Ambient air is thus drawn into the cabin. Thedischarge from the compressor passes through the air turbineformechanical energy recovery, and is discharged overboard throughopening 68. Y I

Various modifications may suggest themselves to those l`skilled'in 'theart without my invention,-and,-hence, IW doliiot'wish to be restricteddeparting from thejlspiritltof to the specic formishown,eor-usesifmentioned, except to the extent indicated in the appendedclaims.

Ii'claim: l: -Air conditioning' apparatus y:operable froma` main engineof an aircraft for conditioning an enclosure thereof, comprising:pumping means for air to be delivered to said enclosure driven by saidengine in accordance with its respective speeds under varied operationalrequirernents; cooling means for cooling the air from said pumping meansincluding an expansion air turbine; a bypass around said turbine; avalve in said bypass; a uid pressure actuated servomotor for motivatingsaid valve; a pilot valve for controlling said servomotor connectedbetween the ends of a oating lever arm; speed responsive means connectedto one end of said lever arm; and iiow rate responsive means for theintake of said pumping means connected to the opposite end of saidlever.

2: Air conditioning apparatus operable from a main engine of an aircraftfor conditioning an enclosure thereof, comprising: pumping means for airto be delivered to said enclosure driven by said engine in accordancewith its respective speeds under varied operational requirements;cooling means for cooling the air from said pumping means including anexpansion air turbine; a bypass around said turbine; a uid pressurecontrolled valve in said bypass; means for controlling said valveincluding a floating lever arm; speed responsive actuating meansconnected to said arm, and electro-magnetic actuating means connected tosaid arm, responsive to the intake ow rate of said pumping means.

3. Air conditioning apparatus operable from a main engine of an aircraftfor conditioning an enclosure thereof, comprising: pumping means for airto be delivered to said enclosure driven by said engine in accordancewith its respective speeds under varied operational requirements;cooling means for cooling the air from said pumping means including anexpansion air turbine; and bypass around said air turbine controlled inaccordance with said engine speed and the intake ow rate of air to saidpumping means.

4. Air conditioning apparatus operable from a main engine of an aircraftfor conditioning an enclosure thereof, comprising: pumping means for airto be delivered to said enclosure driven by said engine and inaccordance with its speed under varied operational requirementconditions; cooling means for cooling the air from said pumping means;and a bypass around said cooling means controlled in accordance withsaid engine speed and the intake flow rate of air to said pumping means.

5. Apparatus for moving a controlled ilow of fluid into an enclosure,comprising: a flow path for conducting said fluid under pressure to saidenclosure; a uid pump; power means for actuating said pump including apower recovery device driven by said iluid and acting to cool saidfluid; a tiuid bypass around said device; and means for controllingfluid iiow through said bypass in response to variations in velocity offluid entering said pumping means.

6. Apparatus for moving a controlled ow of iluid into an enclosure,comprising: a ow path for conducting said uid under pressure to saidenclosure; a fluid pump; power means for actuating said pump including apower recovery device driven by said fluid and acting to cool saidfluid; a fluid bypass around said device; and means for regulating tiuidflow through said bypass in response to speed variations of said powerdevice. l

7. Air conditioning apparatus for an enclosure cornprising: power drivenair pumping means having an outlet; an air expansion turbine having aninlet and an outlet, the outlet being connected with said enclosure; aheat exchanger having ow paths in heat exchange relation, one of saidpaths connecting said pumping means outlet and said turbine inlet, andthe other of said paths being connected with a coolant source; a bleedconnection with the outlet of said pumping means; and an air movingmeans activated by bleed air from said connection for circulating saidcoolant.

8. Means for conditioning an enclosure, comprising: power driven airpumping means having an inlet and outlet; air cooling means having aninlet and an outlet, the inlet of which is connected to the outlet ofsaid air pumping means; duct means normally connecting said coolingmeans outlet to said enclosure, whereby cooled air normally-Iowsintosaid eiiclosre through said duct; and a connection 'including valvemeans exterior of said enclosure for selectively disconnecting-saidductfniians with relspect'to' said cooling means, land connecting'lsaidf duct to saidfairpumping" means' inlet,"'wherebyfairl ow `through said'duct"m'e'"ans 'is' 'reversed and air is' pumped from saidericlo'sure'byoperation of said pumping'me'ns. 9. Means for conditioning an enclosure,comprising: power driven air pumping means having an inlet and outlet;air cooling means connected to receive pumped air from said pumpingmeans outlet; duct means for normally conducting air to said enclosurefrom said air cooling means, whereby cooled air normally flows into saidenclosure; and means for selectively disconnecting said duct means withrespect to said cooling means and connecting it to said inlet, wherebyair is pumped from said enclosure by operation of said pumping means.

l0. The method of conditioning air for an enclosure ot' an aircrafthaving a main engine, which comprises the steps of: pumping theconditioning air in accordance with main engine operating speeds;conducting the pumped air to said enclosure through a path includingparallel portions; cooling the air in one of said portions b y passingthrough an expansion air turbine; and controlling flow through the otherportion in accordance with the main engine speed and pumping intake flowrate.

ll. The method of conditioning air for an enclosure of an aircrafthaving a main engine, which comprises the steps of: pumping theconditioning air in accordance with main engine operating speeds;conducting the pumped air to said enclosure through a path includingparallel portions; cooling the air passing through one of said portions;and controlling ow through the other portion in accordance with the mainengine speed and pumping intake low rate.

l2. Means for conditioning an enclosure, comprising: power driven airpumping means having an inlet and outlet; air cooling means, first ductmeans connecting said outlet to said enclosure through said air coolingmeans; an atmospheric discharge port in said duct between said coolingmeans and said enclosure; a second duct connecting said inlet with saidduct means downstream from said cooling means; and valves selectivelyoperable to one position for closing said port and disconnecting saidsecond duct with respect to said first duct means and said inlet, andoperable to another position for opening said port and connecting saidsecond duct with said first duct means and said inlet.

13. Means for conditioning an enclosure, comprising: power driven airpumping means having an inlet and outlet; air cooling means; rst ductmeans connecting said outlet to said enclosure through said air coolingmeans; an atmospheric discharge port in said duct between said coolingmeans and said enclosure; a second duct connecting said inlet with saidduct means downstream from said cooling means; a valve operable toconnect and disconnect said second duct at one end with respect to saidinlet; and a valve at the other end of said second duct operable toclose said port and disconnect said second duct with respect to said rstduct, and open said port and connect said second duct with respect tosaid first duct.

14. Means for conditioning an enclosure, comprising: power driven airpumping means having an inlet and outlet; air cooling means; first ductmeans connecting said outlet to said enclosure through said air coolingmeans; an atmospheric discharge port in said duct between said coolingmeans and said enclosure; a second duct connecting said inlet with saidduct means downstream from said cooling means; a valve operable `toconnect and disconnect said second duct at one end with respect to saidinlet; and a valve at the other end of said second duct operable toclose said port and disconneet said second duct with respect to said rstduct, and open said port and connect said second duct with respect tosaid first duct; and means for simultaneously actuating said valves.

References Cited in the tile of this patent UNITED STATES PATENTS NumberName Date 2,119,402 Puler May 31, 1938 2,390,487 Lawrence et al. Dec. 4,1945 (Other references on following page) Number 7 UNITED STATES PATENTSName Date Larrecq Ian. 15, 1946 Sparrow June 28, 1949 Wood Aug. 23, 1949Morris June 19, 1951 Number 50 Number 8 Name Date- Messinger Feb. 12,1952 FOREIGN PATENTS Country Date France Sept. 1, 1942

